Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C720C433F5 for ; Thu, 16 Dec 2021 21:52:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234627AbhLPVw2 (ORCPT ); Thu, 16 Dec 2021 16:52:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240629AbhLPVv7 (ORCPT ); Thu, 16 Dec 2021 16:51:59 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B864BC06173F; Thu, 16 Dec 2021 13:51:58 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 007FBB8258A; Thu, 16 Dec 2021 21:51:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F3DDC36AE7; Thu, 16 Dec 2021 21:51:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1639691515; bh=bk75P97h4nWD6jek//UN5pHtK2Op57RnCQgGYyF+oTw=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=npjXcb/pbjuFvIu3l0WqxOakxucYPCJx8fZD3vZyqVptasTKuJOfXgxq+1j7IoFB7 2ZD+vCp+8zu4L5lVLr7rqdwABN5MvVIL+Ax39qtMnM14Re3pV7aStFrjraTREd/0CC rDcGqkT0zHdADDowlNaRYYll2wRZFH3ksm+VUDVYTeLk8ww+IMXZMN8dAntbwM03hG FpUn3LpeqS82d5wlbSYpHHp3OcHIez3jT2jUHgJzKrZUVx4nxTRA/fvhaP7QQjwRCD AooNNwJ9OKRTVFLZXO+WGTLZOk90ARoVw3RTkjwkyKOGkPknMNyEHQnQ++di1s1sre PwIAEUL5b7u+Q== Date: Thu, 16 Dec 2021 13:51:55 -0800 (PST) From: Stefano Stabellini X-X-Sender: sstabellini@ubuntu-linux-20-04-desktop To: Oleksandr Tyshchenko cc: xen-devel@lists.xenproject.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Rob Herring , Oleksandr Tyshchenko , Stefano Stabellini , Julien Grall Subject: Re: [PATCH V4 6/6] dt-bindings: xen: Clarify "reg" purpose In-Reply-To: <1639136201-27530-1-git-send-email-olekstysh@gmail.com> Message-ID: References: <35ee3534-9e24-5a11-0bf1-a5dd0b640186@gmail.com> <1639136201-27530-1-git-send-email-olekstysh@gmail.com> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 10 Dec 2021, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko > > Xen on Arm has gained new support recently to calculate and report > extended regions (unused address space) safe to use for external > mappings. These regions are reported via "reg" property under > "hypervisor" node in the guest device-tree. As region 0 is reserved > for grant table space (always present), the indexes for extended > regions are 1...N. > > No device-tree bindings update is needed (except clarifying the text) > as guest infers the presence of extended regions from the number > of regions in "reg" property. > > Signed-off-by: Oleksandr Tyshchenko Acked-by: Stefano Stabellini > --- > Changes V2 -> V3: > - new patch > > Changes V3 -> V4: > - add Stefano's R-b and Rob's A-b > - remove sentence about ACPI for "reg" and "interrupts" > properties > > Changes V4 -> V4.1 > - bring the mentioning of ACPI back which, as was pointed out by Julien, > fits in the context: > https://lore.kernel.org/xen-devel/9602b019-6c20-cdc7-23f3-9e4f8fd720f6@xen.org/T/#t > so technically restore V3 state > - remove Stefano's R-b and Rob's A-b as I am not 100% sure they are > happy with that > --- > Documentation/devicetree/bindings/arm/xen.txt | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/Documentation/devicetree/bindings/arm/xen.txt b/Documentation/devicetree/bindings/arm/xen.txt > index db5c56d..156fe10b 100644 > --- a/Documentation/devicetree/bindings/arm/xen.txt > +++ b/Documentation/devicetree/bindings/arm/xen.txt > @@ -7,10 +7,14 @@ the following properties: > compatible = "xen,xen-", "xen,xen"; > where is the version of the Xen ABI of the platform. > > -- reg: specifies the base physical address and size of a region in > - memory where the grant table should be mapped to, using an > - HYPERVISOR_memory_op hypercall. The memory region is large enough to map > - the whole grant table (it is larger or equal to gnttab_max_grant_frames()). > +- reg: specifies the base physical address and size of the regions in memory > + where the special resources should be mapped to, using an HYPERVISOR_memory_op > + hypercall. > + Region 0 is reserved for mapping grant table, it must be always present. > + The memory region is large enough to map the whole grant table (it is larger > + or equal to gnttab_max_grant_frames()). > + Regions 1...N are extended regions (unused address space) for mapping foreign > + GFNs and grants, they might be absent if there is nothing to expose. > This property is unnecessary when booting Dom0 using ACPI. > > - interrupts: the interrupt used by Xen to inject event notifications. > -- > 2.7.4 >